Effects of Pollution on Pregnancy and Infants

The fetus is particularly susceptible to environmental contaminants as it is developing at the time of pregnancy and is, therefore, more susceptible to their effects. Pregnancy loss, which includes stillbirth and spontaneous abortion (miscarriage), preterm labor and delivery, and neonatal death, is the worst pregnancy outcome. Stunting and its related health and developmental effects are particularly common in populations living in underdeveloped countries or those exposed to high levels of particle pollution. Several environmental toxins can affect an embryo, fetus, or infant as they are developing. This study explores the following questions: What part do pesticides, heavy metals, dioxin derivatives, and polychlorinated diphenyl compounds play as macroenvironmental pollutants in mutagenesis and teratogenesis? What effects do substances that exposed persons have considerable control over, such as alcohol, narcotics, and tobacco smoke, have on the microenvironment? What consequences should practitioners be aware of these toxins in terms of ethics and the law? This study seeks to assess pertinent primary scientific studies on how pollution affects the health of the fetus and newborn during pregnancy.

Short Linear Motifs Characterizing Snake Venom and Mammalian Phospholipases A2

Snake venom phospholipases A2 (PLA2s) have sequences and structures very similar to those of mammalian group I and II secretory PLA2s, but they possess many toxic properties, ranging from the inhibition of coagulation to the blockage of nerve transmission, and the induction of muscle necrosis. The biological properties of these proteins are not only due to their enzymatic activity, but also to protein–protein interactions which are still unidentified. Here, we compare sequence alignments of snake venom and mammalian PLA2s, grouped according to their structure and biological activity, looking for differences that can justify their different behavior. This bioinformatics analysis has evidenced three distinct regions, two central and one C-terminal, having amino acid compositions that distinguish the different categories of PLA2s. In these regions, we identified short linear motifs (SLiMs), peptide modules involved in protein–protein interactions, conserved in mammalian and not in snake venom PLA2s, or vice versa. The different content in the SLiMs of snake venom with respect to mammalian PLA2s may result in the formation of protein membrane complexes having a toxic activity, or in the formation of complexes whose activity cannot be blocked due to the lack of switches in the toxic PLA2s, as the motif recognized by the prolyl isomerase Pin1.

Purification, crystallization and preliminary X-ray diffraction analysis of crotamine, a myotoxic polypeptide from the Brazilian snake Crotalus durissus terrificus

Crotamine, a highly basic myotoxic polypeptide (molecular mass 4881 Da) isolated from the venom of the Brazilian rattlesnake Crotalus durissus terrificus, causes skeletal muscle contraction and spasms, affects the functioning of voltage-sensitive sodium channels by inducing sodium influx and possesses antitumour activity, suggesting potential pharmaceutical applications. Crotamine was purified from C. durissus terrificus venom; the crystals diffracted to 1.9 Å resolution and belonged to the orthorhombic space group I2(1)2(1)2(1) or I222, with unit-cell parameters a = 67.75, b = 74.4, c = 81.01 Å. The self-rotation function indicated that the asymmetric unit contained three molecules. However, structure determination by molecular replacement using NMR-determined coordinates was unsuccessful and a search for potential derivatives has been initiated.

Crystallization and preliminary X-ray crystallographic studies of a Lys49-phospholipase A2 homologue from Bothrops pirajai venom complexed with rosmarinic acid

PrTX-I, a noncatalytic and myotoxic Lys49-phospholipase A(2) from Bothrops pirajai venom, was crystallized in the presence of the inhibitor rosmarinic acid (RA). This is the active compound in the methanolic extract of Cordia verbenacea, a plant that is largely used in Brazilian folk medicine. The crystals diffracted X-rays to 1.8 A resolution and the structure was solved by molecular-replacement techniques, showing electron density that corresponds to RA molecules at the entrance to the hydrophobic channel. The crystals belong to space group P2(1)2(1)2(1), indicating conformational changes in the structure after ligand binding: the crystals of all apo Lys49-phospholipase A(2) structures belong to space group P3(1)21, while the crystals of complexed structures belong to space groups P2(1) or P2(1)2(1)2(1).